Thank you very much for your response as I now know where and what to look for in my university library. I checked the reference website and we have this text by Kittel and Kroemer. Thank you once again for the response.
This is not a homework problem, this is a question borne out of self-interest.
I picked up the book "The Dreams that Stuff is Made of" by Stephen Hawking:
(https://www.amazon.com/dp/0762434341/?tag=pfamazon01-20 )
and read the first article by Max Planck: "On the Distribution of Energy in the...